No standby light and when on pressing the volume buttons makes it glitch

[Klm6]

Had the tv for a few months and all has been good. For the past 10 days it has started glitching. The sound isn't working even though when I press the volume button the side bar on the screen shows it going  up or down. The volume buttons cause it to pause and then the programme plays but no sound. Or the sound will come on but it cannot be adjusted. Also if the sound is working and when it's turned off by the remote the screen may go blank but the sound continues. 
sometimes things are rectified by turning off at the plug but mostly not. 

The stand by light also isn't lit at all, any time 

[Mr+Flibbles+86]

Hi there, I’ve escalated your post to our Community Messaging team who will invite you to a private chat shortly and help you with this. 

Just look out for the colourful bubble to start the conversation.

Here's more information on how Community Messaging works - https://helpforum.sky.com/t5/Did-you-know/Escalating-a-post-to-a-Sky-expert/ba-p/3711147